Drawbar or hitch for agricultural implements



Feb. 12, 1946. G. M. BOUMPHREY DRAW BAR OR HITCH FOR AGRICULTURAL IMPLEMENTS 2 Sheets-Sheet 1 I nvenlor I Filed Feb. 1, 1944 Aitbrneys (m offrg flaxwell Boum vhrgf Feb. 12, 1946. G. M. BOUMPHREY DRAW BAR 0R HITCH FOR AGRICULTURAL IMPLEMENTS 2 Sheets-Sheet 2 Filed Feb. 1, 1944 I nvenlor Geoffrcfkfllaxwell BouWl/Qhff/ Patented Feb. 12, 1946 'DRAWBAR OR HITCH FOR AGRICULTURAL IMPLEMENTS Geoffrey Maxwell" Boumphrey, iersliore; England '1; Application February 1, 1944, SeriaL.No-.;520,584

In Great Britain February 26, 1943 1 Claim. (01. BSD-33.12)

This invention relates to drawbars or hitches used to couple ploughs and other agricultural implements to the power means by which they are drawn, such as a tractor, of the kind having coupling pin, said end parts being connected by a air of spaced limbs 6 which acts as a guide for a nut 1. Integral with the nut are a pair of opposed trunnions 8 on which are journally provision for adjusting the angle of draught. u d a p f spa d links nst tuti th The invention provides improved means by arm 3 to couple the adjustable member I with the which the angle aforesaid can be satisfactorily transverse member 2. adjusted while the implement is working, i. e. Between the two spaced limbs B and rotatably without having to stop the tractor or other means carried in the two end parts 9, I0, of the adjustof tractionable member (conveniently in bearings of footstep The invention provides an improved mechaor spigot character with interposed ball II or nism for adjusting the angle of draught of the other anti-friction device) is a screwed shaft l2 kind havin a triangular frame, One member of engaging the nut and adapted for rotation in which is transverse to the direction of traction either direction by ratchet and pawl device l3 and attached to the implement to be drawn, anmounted on one end of the shaft. other of which is substantially in the direction Such device shown enlarged in Figs. 3 and 4 of traction and the third is inclined to both direcincludes a toothed wheel I4 keyed or otherwise ticns, either the second or third member being fixed to the shaft l2, a strap [5 oscillatable on adjustable in length to vary the angle of draught. the shaft, a sleeve like lever arm I6 secured to The object of the present invention is to prothe strap and a pawl member I! in the lever arm vide a mechanism of the kind above referred to Hi. Provision is made whereby the one pawl is having in combination a mechanism having an selectively brought into action for the turning of operating member which is given a to and fro the wheel in the direction desired, such for exmovement which is operative in one direction and ample as by straight-flanked teeth and by the idle in the opposite direction and means whereby incorporation of the p w oth N at he lower the operative and idle directions of movement end of the pawl spindle I! movable about its may be reversed. axis to present the pawl to the wheel teeth in With these and other objects in view the ineither of two positions spaced apart angularly by vention consists in the improved combinations 180. The spindle I1 is also movable rectilinearly and arrangements of parts set out in the embodiin its sleeve mounting Hi to enable it to be disment which will now be described in relation to engaged radially from the wheel l5 and re-enthe accompanying drawings, the novel features gaged after adjustment to the other angular posibeing recited in the claim which follows. tion; this movement is conveniently efiected In these drawings: through the agency of a handle l9 at the outer Figs. 1 and 2 show in elevation and plan, one protruding part of the spindle and a coiled spring embodiment of the invention, or springs 20 which hold the pawl tooth in con- Figs. 3 and 4 show on an enlarged scale, a onetact with the teeth. Alternatively, two one-way way device included in Figs. 1 and 2. pawls may be used in conjunction with means by In the arrangement depicted in the drawings, which the one or the other can be made operative. three members are articulated together in a tri- Oscillation of the lever arm produces a to-andangular formation, one I lying more or less in fro motion of the pawl and consequent turning the direction of travel of the implement, one 2 of the screwed shaft in or relative to the nut transverse thereto, and the third 3 inclined to which is thus either advanced or retrogressed both directions. At the median position of adcarrying with it the attached end of the hypotejustment, the triangle is substantially a right nuSe member 3 in the line of travel of the maangle one with the base member 2 connected to chine. The transverse draught bar 2 is turned the plough or other implement, the hypotenuse about its fulcrum point on the adjustable meminclined as aforesaid, and the other side I adjustber I, and the angle of draught varied within the able in effective length to vary the angle. limits of the device to the extent desired while The adjustable member I is invariable as to its the machine is travelling. The range coverable overall length and carries the adjusting means may be augmented by placing the coupling pins intermediate its ends. One end has a slotted hole in any one of the several holes provided at each 4 or other expedient for connecting to the tractor end of the draught bar at the two articulation bar, hook, or the like, and the other and rear end zones.

has several holes 5 for selective insertion of a The screwed shaft with its one-way device may 2; r H V 2,394,744;

be enclosed by upper and lower cover plates with 1 slots for movement of the trunnions and the rock lever, with or without sliding covers over the slots, to exclude soil, etc. 7

The adjusting device may be placed at either end of the adjustable member within reach of the driver for direct actuation, or operated by remote control mechanism similar to that used in connection with the gear shifts of self-propelled vehicles 7 r I claim:

Means for adjusting the angle of draught during'traction of ploughs and other agricultural implements employing a triangular frame, one 3 1 member of which is transverse to the direction of nism having an operating member which is given v connected to the draught bar or its equivalent,

a toothed wheelon said screw, a lever arm jouri nally mounted with respect to the wheel, and pawl I means carried on the lever arm for selective entraction and attached to the implement to be drawn, another of which is substantially in the a to and fro movement which is'operative in one directionand idle in the opposite direction, said mechanism including in combinations. screwed shaft,,a nut engaging the screw and operatively gagement with the toothed wheel to enable the angle of draught to be varied in either sense.

H BOUMIPHREY.

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